Pour batter into a 10" square cake pan. Bang the pan on the countertop until you see air bubbles come to the surface and pop. This will eliminate crumbs in the completed cake and make it a smooth, moist, rich cake.

Bake at 325 degrees for one hour until golden brown. Bake at this lower temperature so that the large square cake gets done in the middle.

After removing the baked cake from the oven, immediately remove from pan and wrap in plastic. Place in the freezer. This will lock the moisture in the cake that would otherwise escape through steam. Freeze over night or up to a month.

When ready to decorate, make the frosting by mixing all ingredients together until smooth.

To decorate, cut about 2 inches off one of the sides of the cake to make a rectangle. Attach the cake in an upright position to a cake board using stiff frosting. Frost the cake. Cover with fondant. Cut and mold fondant into shapes to make the buttons on the karaoke machine and a microphone. Use a food coloring pen to write the age of the birthday child on "song number display" and the child's name on a tag that represents the brand of the machine.